GMC 2005 Sierra 1500 Pickup Owner's Manual page 118

DRIVE (D): This position is for normal driving. If you
need more power for passing, and you are:
•
Going less than about 35 mph (55 km/h), push your
accelerator pedal about halfway down.
•
Going about 35 mph (55 km/h) or more, push the
accelerator all the way down.
You will shift down to the next gear and have more
power.
DRIVE (D) can be used when towing a trailer, carrying a
heavy load, driving on steep hills or for off-road
driving. You may want to shift the transmission to
THIRD (3) or, if necessary, a lower gear selection if the
transmission shifts too often.
If your vehicle is equipped with the Allison
®
Transmission , it will initially attain first range when
DRIVE (D) is selected. As vehicle speed increases, the
transmission will upshift automatically through each
available range up to FIFTH (5). As the vehicle slows,
the transmission will downshift automatically.
The Allison Transmission
feature to adjust the transmission shift schedule to the
current driving situation to reduce rapid upshifts and
downshifts. This shift stabilization feature is designed to
determine before making an upshift if the engine will
be able to maintain vehicle speed by analyzing
things such as throttle position, vehicle load, and hill
grade. If the shift stabilization feature determines
2-28
®
uses a shift stabilization
that current vehicle speed cannot be maintained, the
transmission does not upshift and instead holds
the current gear. In some cases, this may appear to be
a hanging shift, however the transmission is operating
normally.
The Allison Transmission
controls. Adaptive shift controls continually compares
key shift parameters to pre-programmed ideal shift
conditions. The Allison Transmission
adjustments to improve vehicle performance according
to the way the vehicle is being used, such as with a
heavy load. During this adaptive shift controls process,
some shifts may feel different as the transmission
determines optimum settings for a particular shift.
By using shift stabilization and adaptive shift controls,
the Allison Transmission
adjusts to how the vehicle is being used, providing
improved vehicle performance.
THIRD (3): This position is also used for normal driving,
however it offers more power and lower fuel economy
than DRIVE (D).
SECOND (2): This position gives you more power but
lower fuel economy. You can use SECOND (2) on
hills. It can help control your speed as you go down
steep mountain roads, but then you would also want to
use your brakes off and on.
®
also uses adaptive shift
®
constantly makes
®
shift schedule is variable and